This invention relates to a mobile communication system and a method of matching current location information for a mobile station and, in particular, to a mobile communication system and a method of matching current location information for a mobile station upon introduction of packet data communication services.
A related mobile communication system will hereinafter be described with reference to the drawing.
Referring to FIG. 1, the related mobile communication system comprises a mobile station (MS) 1, first and second radio networks (RN) 2 and 18, a mobile services-switching center (MSC) 3, and a home location register (HLR) 4. In mobile communication, location registration is generally carried out as follows. It is assumed that the MS 1 is turned on within a first service area assigned to the first RN 2 or that the MS 1 being moved enters into the first service area. In this event, the MS 1 transmits a location registration update request signal through the first RN 2 and the MSC 3 to the HLR 4. The HLR 4 preliminarily memorizes subscriber data associated with the MS 1 and including current location information representative of a current location of the MS 1, i.e., a service area where the MS 1 is present. In response to the location registration update request signal, the HLR 4 updates the current location information memorized therein so that the current location information indicates the first service area assigned to the first RN 2.
When a call signal addressed to the MS 1 is received from a public telephone network, the MSC 3 refers to the current location information and transmits the call signal to the first RN 2 corresponding thereto.
In the recent mobile communication environment, data communication services are introduced. In particular, high-speed packet data communication services utilizing packet communication are started and operated in a large scale.
In the packet data communication services, user data are transmitted and received between the MS 1 and a packet data communication network through the first RN 2 and a packet gateway (PGW) 6 without passing through the MSC 3.
A communication network generally called an internet represents one mode of the packet data communication network.
Therefore, the PGW 6 is required to continuously grasp which RN is to be selected for transmission of the user data following the movement of the MS 1. For this purpose, a so-called home agent (HA) 7 for managing the current location information is required for the packet data communication services.
In correspondence to the HA 7, the first and the second RN 2 and 18 are provided with first and second foreign agents (FA) 8, respectively. Between the HA 7 and each of the first and the second FAs 8 and 19, update management for the current location information associated with the MS 1 is continuously carried out.
A communication protocol to be used herein is under research and investigation in various countries in the world on the basis of MIP (Mobile Internet Protocol) <RFC2026 et al>constructed by IETF (Internet Engineering Task Force) which is an international internet protocol research organization.
In an interim result of research, the basic concept is such that the MS 1 periodically transmits a “current location report” to the first or the second RN 2 or 18 and, in response to the current location report, the update management for the current location information associated with the mobile station 1 is carried out between the first or the second FA 8 or 19 and the HA 7.
However, in the conventional mobile communication system and the method of matching the current location information for the mobile station, the current location information for each single MS is doubly managed individually by the HLR for ordinary mobile communication and by the HA for the packet data communication. At present, there is no arrangement or means for matching the current location information between the HLR and HA. This inevitably results in mismatching in MS registration state or latest current location information.
Upon occurrence of mismatching in current location information, the call signal or the user data will undesirably be transmitted to a different RN having a service area where the MS is not present.
In case where the “current location report” is periodically transmitted as mentioned above in order to update the current location information in the HA, traffic in a radio section is increased. This results in suppression of efficiency of use of a radio channel intended for speech communication and data communication.